This is why we keep feeling so many relatively small earthquakes lately

The USGS said earthquakes are felt at farther distances on the east coast compared to ones that hit the west coast.

Author:
Tim Pham, WRCB

Published:
3:18 PM EST December 12, 2018

Updated:
12:03 AM EST December 16, 2018

(WRCB) From Nashville to Atlanta, people from across the southeast report they felt Wednesday's earthquake, which the U.S. Geological Survey said originated near Decatur, Tennessee. Geologists said this is typical for this region of the country.

Some people slept right through it. Others felt the 4.4 earthquake right at 4:14 am.

It isn't a coincidence many people felt this one. The USGS said earthquakes are felt at farther distances on the east coast compared to ones that hit the west coast.

In the east, the bedrock is older, more firm and not tectonically disturbed, which researchers say allows seismic waves to cross them more effectively during an earthquake.

"It just transmits the seismic energy that much more efficiently than the bedrock on the west or western North America," Dr. Jonathan Mies, a University of Tennessee at Chattanooga geology professor, explained.

On the west coast, the bedrock is tectonically active and more prone to frequent earthquakes. Dr. Mies said this 4.4 is more broadly felt on this side of the country. He added, when, not if a big earthquake hits this area, the impact could be more damaging than in other parts of the country.

"That transmission of seismic energy is likely to contribute to more far-reaching and more intense damaging consequences of an earthquake here," he explained.

Because people in this region are not used to experiencing earthquakes, Dr. Mies said it's important that each family make a plan at home, school or the office.

"We're simply not prepared. Our structures, buildings and infrastructure are not built with earthquakes in mind," Dr. Mies said.

With so many earthquakes out west, Dr. Mies says the bedrock is fragmented and separated by faults which means seismic waves won't travel as far. This explains why folks out there might only feel a quake near the epicenter.

"The people there would be so desensitized to movement like that, that they wouldn't even, they wouldn't care," he said.

According to the National Weather Service office in Morristown, the largest earthquake on record in East Tennessee was a magnitude 4.7 near Maryville in 1973.

Officials say one of the most important takeaways is to make sure everyone should know how to protect themselves during an earthquake. Check out FEMA's "Ready Campaign" for tips on earthquake preparedness.